Atherectomy Devices and Methods

ABSTRACT

Rotational atherectomy devices and systems can remove or reduce stenotic lesions in blood vessels by rotating one or more abrasive elements within the vessel. The abrasive elements can be attached to a distal portion of an elongate flexible drive shaft that extends from a handle assembly that includes a driver for rotating the drive shaft. In particular implementations, individual abrasive elements are attached to the drive shaft at differing radial angles in comparison to each other (e.g., configured in a helical array). The centers of mass of the abrasive elements can define a path that fully or partially spirals around the drive shaft. In some embodiments, a distal stability element with a center of mass aligned with the longitudinal axis is fixedly mounted to the drive shaft.

TECHNICAL FIELD

This document relates to rotational atherectomy devices and systems forremoving or reducing stenotic lesions in blood vessels, for example, byrotating an abrasive element within the vessel to partially orcompletely remove the stenotic lesion material.

BACKGROUND

Atherosclerosis, the clogging of arteries with plaque, is often a resultof coronary heart disease or vascular problems in other regions of thebody. Plaque is made up of fat, cholesterol, calcium, and othersubstances found in the blood. Over time, the plaque hardens and narrowsthe arteries. This limits the flow of oxygen-rich blood to organs andother parts of the body.

Blood flow through the peripheral arteries (e.g., carotid, iliac,femoral, renal etc.), can be similarly affected by the development ofatherosclerotic blockages. Peripheral artery disease (PAD) can beserious because without adequate blood flow, the kidneys, legs, arms,and feet may suffer irreversible damage. Left untreated, the tissue candie or harbor infection.

One method of removing or reducing such blockages in blood vessels isknown as rotational atherectomy. In some implementations, a drive shaftcarrying an abrasive burr or other abrasive surface (e.g., formed fromdiamond grit or diamond particles) rotates at a high speed within thevessel, and the clinician operator slowly advances the atherectomydevice distally so that the abrasive burr scrapes against the occludinglesion and disintegrates it, reducing the occlusion and improving theblood flow through the vessel.

SUMMARY

Some embodiments of rotational atherectomy systems described herein canremove or reduce stenotic lesions in blood vessels by rotating one ormore abrasive elements to abrade and breakdown the lesion. Someembodiments can abrade stenotic lesions in blood vessels by rotating theabrasive element(s) according to a stable and predictable orbitingprofile. In some embodiments, the abrasive element(s) are attached to adistal portion of an elongate flexible drive shaft that extends from ahandle assembly. In particular embodiments, a rotational atherectomydevice comprises an elongate flexible drive shaft with multipleeccentric abrasive elements that are attached to the drive shaft, andone or more weighted stability elements are attached to the drive shaftsuch that at least one stability element is distal of the abrasiveelement. Optionally, the stability elements have a center of mass thatis axially aligned with a central longitudinal axis of the drive shaftwhile the eccentric abrasive element(s) has a center of mass that isaxially offset from central longitudinal axis of the drive shaft.

In some embodiments, multiple abrasive elements are coupled to the driveshaft and are offset from each other around the drive shaft such thatthe centers of the abrasive elements are disposed at differing radialangles from the drive shaft in relation to each other. For example, insome embodiments a path defined by the centers of mass of the abrasiveelements defines a spiral around a length of the central longitudinalaxis of the drive shaft. A flexible polymer coating may surround atleast a portion of the drive shaft, including the stability element(s)in some embodiments. Also, in some optional embodiments, a distalextension portion of the drive shaft may extend distally beyond thedistal-most stability element.

In one aspect, this disclosure is directed to a rotational atherectomydevice for removing stenotic lesion material from a blood vessel of apatient. In some embodiments, the rotational atherectomy deviceincludes: (i) an elongate flexible drive shaft comprising atorque-transmitting coil and defining a longitudinal axis, the driveshaft being configured to rotate about the longitudinal axis; (ii) firstand second abrasive elements attached to a distal end portion of thedrive shaft and each having a center of mass offset from thelongitudinal axis, the center of mass of the first abrasive elementbeing offset from the longitudinal axis at a first radial angle, thecenter of mass of the second abrasive element being offset from thelongitudinal axis at a second radial angle that differs from the firstradial angle; and (iii) a distal stability element fixedly mounted tothe drive shaft and having a center of mass aligned with thelongitudinal axis, the distal stability element being distally spacedapart from the first and second abrasive elements.

Such a rotational atherectomy device may optionally include one or moreof the following features. The device may also include a third abrasiveelement attached to the distal end portion of the drive shaft. Thecenter of mass of the third abrasive element may be offset from thelongitudinal axis along a third radial angle that differs from the firstradial angle and the second radial angle. The second radial angle maydiffer from the first radial angle by at least 15 degrees. The thirdradial angle may differ from the first radial angle and the secondradial angle by at least 15 degrees. The distal stability element maycomprise a metal cylinder surrounding the torque-transmitting coil ofthe drive shaft and having a maximum diameter smaller than the first andsecond abrasive elements, and wherein the distal stability element hasan abrasive outer surface. The device may also include an array ofabrasive elements including the first and second abrasive elements andadditional abrasive elements attached to the distal end portion of thedrive shaft. In some embodiments, a proximal-most one of the array ofabrasive elements and a distal-most one of the array of abrasiveselement are each smaller than intermediate ones of the array of abrasiveelements. A path defined by the centers of mass of the array of abrasiveelements may define at least a portion of a helical path around thelongitudinal axis. The device may also include a flexible polymercoating along the drive shaft such that the coating surrounds an outerdiameter of at least a portion of drive shaft.

In some embodiments, the rotational atherectomy device also includes:(iv) an actuator handle assembly configured to drive rotation of thedrive shaft about the longitudinal axis, the actuator handle assemblycomprising a carriage assembly that is movable in relation to otherportions of the actuator handle assembly to translate the drive shaftalong the longitudinal axis; and (v) a sheath extending from theactuator handle assembly, the drive shaft slidably disposed within alumen defined by the sheath.

In another aspect, this disclosure is directed to a rotationalatherectomy device for removing stenotic lesion material from a bloodvessel of a patient. In some embodiments, the rotational atherectomydevice includes: (a) an elongate flexible drive shaft comprising atorque-transmitting coil and defining a longitudinal axis, the driveshaft being configured to rotate about the longitudinal axis; (b) ahelical array of abrasive elements attached to a distal end portion ofthe drive shaft, each of the abrasive elements having a center of massthat is offset from the longitudinal axis, the centers of mass of theabrasive elements being noncollinear; and (c) a distal stability elementaffixed to the drive shaft and having a center of mass aligned with thelongitudinal axis, the distal stability element distally spaced apartfrom the plurality of abrasive elements.

Such a rotational atherectomy device may optionally include one or moreof the following features. The device may also include a flexiblepolymer coating along the drive shaft such that the coating surrounds anouter diameter of at least a portion of drive shaft. The drive shaft mayinclude a distal-most extension portion that extends distally of thedistal stability element for a distal extension distance. The driveshaft may have a central lumen configured to receive a guidewireextending along the longitudinal axis. The distal stability element maycomprise a metal cylinder surrounding the torque-transmitting coil, andwherein the metal cylinder has an abrasive outer surface. The pluralityof abrasive elements may be spaced apart from each other by at least 50%of an outer diameter of a largest one of the abrasive elements. Aproximal-most one of the abrasive elements and a distal-most one of theabrasives element may each be smaller than intermediate ones of theabrasive elements. A path defined by the centers of mass of sequentialabrasive elements of plurality the abrasive elements may spiral aroundthe longitudinal axis. The plurality of abrasive elements may include atleast five abrasive elements.

In another aspect, this disclosure is directed to a system forperforming rotational atherectomy to remove stenotic lesion materialfrom a blood vessel of a patient. In some embodiments, the systemincludes: 1) an elongate flexible drive shaft comprising atorque-transmitting coil and defining a longitudinal axis, the driveshaft being configured to rotate about the longitudinal axis; 2) one ormore abrasive elements attached to a distal end portion of the driveshaft, each of the abrasive elements having a center of mass that isoffset from the longitudinal axis; 3) a distal stability element fixedto the drive shaft and having a center of mass aligned with thelongitudinal axis, the distal stability element distally spaced apartfrom the plurality of abrasive elements; 4) an actuator handle assemblyconfigured to drive rotation of the drive shaft about the longitudinalaxis, the actuator handle assembly comprising a carriage assembly thatis movable in relation to other portions of the actuator handle assemblyto translate the drive shaft along the longitudinal axis; 6) a sheathextending from the actuator handle assembly, the drive shaft slidablydisposed within a lumen defined by the sheath; and 7) a controlleroperably coupleable to the actuator handle assembly, the controllerconfigured to provide output to the actuator handle assembly that causesthe actuator handle assembly to drive the rotation of the drive shaftabout the longitudinal axis. The controller can include a user interfacewith a plurality of selectable inputs corresponding to a plurality ofvessel sizes. The controller may be configured to provide a respectiveoutput to the actuator handle assembly that differs for each of thevessel sizes.

Such a system for performing rotational atherectomy to remove stenoticlesion material from a blood vessel of a patient may optionally includeone or more of the following features. A center of mass of a first oneof the abrasive elements may be transversely offset from thelongitudinal axis along a first angle. A center of mass of a second oneof the abrasive elements may be transversely offset from thelongitudinal axis along a second angle that differs from the first angleby at least 15 degrees. The system may also include a flexible polymercoating along the drive shaft such that the coating surrounds an outerdiameter of at least a portion of drive shaft. In some embodiments, thedistal stability element has an abrasive outer surface.

In another aspect, this disclosure is directed to a method forperforming rotational atherectomy to remove stenotic lesion materialfrom a blood vessel of a patient. In some embodiments, the methodincludes: delivering a rotational atherectomy device into the bloodvessel and rotating the drive shaft about the longitudinal axis suchthat the abrasive elements orbit around the longitudinal axis. In someembodiments, the rotational atherectomy device includes: (a) an elongateflexible drive shaft comprising a torque-transmitting coil and defininga longitudinal axis, the drive shaft being configured to rotate aboutthe longitudinal axis; (b) a helical array of abrasive elements attachedto a distal end portion of the drive shaft, each of the abrasiveelements having a center of mass that is offset from the longitudinalaxis, the centers of mass of the abrasive elements arranged along a paththat spirals around the longitudinal axis; and (c) a distal stabilityelement affixed to the drive shaft and having a center of mass alignedwith the longitudinal axis, the distal stability element distally spacedapart from the plurality of abrasive elements.

Some of the embodiments described herein may provide one or more of thefollowing advantages. First, some embodiments of the rotationalatherectomy system are configured to advance the drive shaft and thehandle assembly over a guidewire, and to drive the rotation of the driveshaft while the guidewire remains within the drive shaft. Accordingly,in some embodiments the handle assemblies provided herein includefeatures that allow the drive shaft to be positioned over a guidewire.Thereafter, the guidewire can be detained in relation to the handle sothat the guidewire will not rotate while the drive shaft is beingrotated.

Second, some embodiments of the rotational atherectomy devices andsystems provided herein include a handle assembly with a carriage thatis manually translatable during rotation of the drive shaft, resultingin longitudinal translation of the rotating abrasive element in relationto a target lesion. In particular embodiments, a valve (or otherconnector) is mounted on the carriage and operable to control a supplyof compressed gas (or other power source) to a carriage-mounted turbinemember. The turbine member rotationally drives the drive shaft of theatherectomy device. Hence, in some embodiments the valve for actuatingthe rotational operation of the drive shaft is conveniently located onthe translatable carriage of the handle assembly. Alternatively, in someembodiments an electric motor is used to drive rotations of the driveshaft.

Third, some embodiments of the rotational atherectomy devices andsystems operate with a stable and predictable rotary motion profile forenhanced atherectomy performance. That is, when the device is beingrotated in operation, the eccentric abrasive element(s) follows apredefined, consistent orbital path (offset from an axis of rotation ofthe device) while the stability element(s) and other portions of thedevice remain on or near to the axis of rotation for the drive shaft ina stable manner. This predictable orbital motion profile can be attainedby the use of design features including, but not limited to, stabilityelement(s) that have centers of mass that are coaxial with thelongitudinal axis of the drive shaft, a polymeric coating on at least aportion of the drive shaft, a distal-most drive shaft extension portion,and the like. Some embodiments of the rotational atherectomy devices andsystems provided herein may include one or more of such design features.

Fourth, some embodiments of the rotational atherectomy devices andsystems provided herein can be used to treat large-diameter vessels(including renal and iliac arteries having an internal diameter that ismultiple time greater than the outer diameter of the abrasive element)while requiring only a small introducer sheath size. In other words, insome embodiments the rotating eccentric abrasive element(s) traces anorbital path that is substantially larger than the outer diameter of therotational atherectomy device in the non-rotating state. This featureimproves the ability of the rotational atherectomy devices providedherein to treat very large vessels while still fitting within a smallintroducer size. In some embodiments, this feature can be at leastpartially attained by using a helical array of abrasive elements thathas a high eccentric mass (e.g., the centers of mass of the abrasiveelements are significantly offset from the central longitudinal axis ofthe drive shaft). Further, in some embodiments this feature can be atleast partially attained by using multiple abrasive elements that areoffset from each other around the drive shaft such that the centers ofthe abrasive elements are not coaxial with each other.

Fifth, in some embodiments the rotational atherectomy devices include adistal stability element that has an abrasive outer surface. In somecases, while the rotational atherectomy device is being advanced withinthe vasculature of a patient, the distal end of the rotationalatherectomy device may encounter lesions that occlude or substantiallyocclude the vessel. In such a case, the abrasive outer surface on thedistal stability element may help facilitate passage of the distalstability element through lesions that occlude or substantially occludethe vessel. In some such cases the drive shaft may be used to rotate thedistal stability element to help facilitate boring of the distalstability element through such lesions in a drill-like fashion.

Sixth, in some embodiments rotational atherectomy systems describedherein include user controls that are convenient and straight-forward tooperate. In one such example, the user controls can include selectableelements that correspond to the diametric size of the vessel to betreated. When the clinician-user selects the particular vessel size, thesystem will determine an appropriate rpm of the drive shaft to obtainthe desired orbit of the abrasive element(s) for the particular vesselsize. Hence, in such a case the clinician-user conveniently does notneed to explicitly select or control the rpm of the drive shaft. Inanother example, the user controls can include selectable elements thatcorrespond to the speed of drive shaft rotations. In some such examples,the user can conveniently select “low,” “medium,” or “high” speeds.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of an example rotational atherectomy systemin accordance with some embodiments.

FIG. 2 shows a guidewire being advanced through a lesion in a bloodvessel.

FIG. 3 shows an example rotational atherectomy device being advancedover the guidewire of FIG. 2 and into region of the lesion.

FIG. 4 shows the example rotational atherectomy device of FIG. 3 in useat a first longitudinal position in the region of the lesion. Amulti-portion abrasive element of the rotational atherectomy device isbeing rotated along an orbital path to abrade the lesion.

FIG. 5 shows the rotational atherectomy device of FIG. 3 with theabrasive element being rotated at a second longitudinal position that isdistal of the first longitudinal position.

FIG. 6 shows the rotational atherectomy device of FIG. 3 with theabrasive element being rotated at a third longitudinal position that isdistal of the second longitudinal position.

FIG. 7 is a longitudinal cross-sectional view of a distal portion of anexample rotational atherectomy device showing a multi-portion abrasiveelement and a distal stability element with an abrasive coating.

FIG. 8 is a side view of a distal portion of another example rotationalatherectomy device showing a multi-portion abrasive element and a distalstability element with an abrasive coating. The individual portions ofthe multi-portion abrasive element are offset from each other around thedrive shaft such that the centers of mass of the abrasive elementportions define a spiral path around the drive shaft axis.

FIG. 9 is a transverse cross-sectional view of the rotationalatherectomy device of FIG. 8 taken along the cutting-plane line 9-9.

FIG. 10 is a transverse cross-sectional view of the rotationalatherectomy device of FIG. 8 taken along the cutting-plane line 10-10.

FIG. 11 is a transverse cross-sectional view of the rotationalatherectomy device of FIG. 8 taken along the cutting-plane line 11-11.

FIG. 12 is a transverse cross-sectional view of the rotationalatherectomy device of FIG. 8 taken along the cutting-plane line 12-12.

FIG. 13 is a transverse cross-sectional view of the rotationalatherectomy device of FIG. 8 taken along the cutting-plane line 13-13.

FIG. 14 shows an example user control unit of a rotational atherectomysystem that is being operated by a clinician-user to perform arotational atherectomy procedure below the knee of a patient.

FIG. 15 shows the example user control unit of FIG. 14 being operated toperform a rotational atherectomy procedure above the knee of a patient.

FIG. 16 shows an example user control unit with another type of userinterface.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIG. 1, in some embodiments a rotational atherectomy system100 for removing or reducing stenotic lesions in blood vessels caninclude a guidewire 134, an actuator handle assembly 110, an elongateflexible drive shaft assembly 130, and a controller 150. The drive shaftassembly 130 extends distally from the handle assembly 110. Thecontroller 150 is connected to the handle assembly 110 via a cableassembly 160. The handle assembly 110 and controller 150 can be operatedby a clinician to perform and control the rotational atherectomyprocedure.

In the depicted embodiment, the elongate flexible drive shaft assembly130 includes a sheath 132 and a flexible drive shaft 136. A proximal endof the sheath 132 is fixed to a distal end of the handle assembly 110.The flexible drive shaft 136 is slidably and rotatably disposed within alumen of the sheath 132. The flexible drive shaft 136 defines alongitudinal lumen in which the guidewire 134 is slidably disposed. Inthis embodiment, the flexible drive shaft 136 includes atorque-transmitting coil that defines the longitudinal lumen along acentral longitudinal axis, and the drive 136 shaft is configured torotate about the longitudinal axis while the sheath 132 remainsgenerally stationary. Hence, as described further below, during arotational atherectomy procedure the flexible drive shaft 136 is inmotion (e.g., rotating and longitudinally translating) while the sheath132 and the guidewire 134 are generally stationary.

In some optional embodiments, an inflatable member (not shown) cansurround a distal end portion of the sheath 132. Such an inflatablemember can be selectively expandable between a deflated low-profileconfiguration and an inflated deployed configuration. The sheath 132 maydefine an inflation lumen through which the inflation fluid can pass (toand from the optional inflatable member). The inflatable member can bein the deflated low-profile configuration during the navigation of thedrive shaft assembly 130 through the patient's vasculature to a targetlocation in a vessel. Then, at the target location, the inflatablemember can be inflated so that the outer diameter of the inflatablemember contacts the wall of the vessel. In that arrangement, theinflatable member advantageously stabilizes the drive shaft assembly 130in the vessel during the rotational atherectomy procedure.

Still referring to FIG. 1, the flexible driveshaft 136 is slidably androtatably disposed within a lumen of the sheath 132. A distal endportion of the driveshaft 136 extends distally of the distal end of thesheath 132 such that the distal end portion of the driveshaft 136 isexposed (e.g., not within the sheath 132, at least not during theperformance of the actual rotational atherectomy).

In the depicted embodiment, the exposed distal end portion of thedriveshaft 136 includes one or more abrasive elements 138, a (optional)distal stability element 140, and a distal drive shaft extension portion142. In the depicted embodiment, the one or more abrasive elements 138are eccentrically-fixed to the driveshaft 136 proximal of the distalstability element 140. In this embodiment, the distal stability element140 is concentrically-fixed to the driveshaft 136 between the one ormore abrasive elements 138 and the distal drive shaft extension portion142. As such, the center of mass of the distal stability element 140 isaligned with the central axis of the drive shaft 136 while the center ofmass of each abrasive element 138 is offset from the central axis of thedrive shaft 136. The distal drive shaft extension portion 142, whichincludes the torque-transmitting coil, is configured to rotate about thelongitudinal axis extends distally from the distal stability element 140and terminates at a free end of the drive shaft 136.

In some optional embodiments, a proximal stability element (not shown)is included. The proximal stability element can be constructed andconfigured similarly to the depicted embodiment of the distal stabilityelement 140 (e.g., a metallic cylinder directly coupled to thetorque-transmitting coil of the drive shaft 136 and concentric with thelongitudinal axis of the drive shaft 136) while being located proximalto the one or more abrasive elements 138.

In the depicted embodiment, the distal stability element 140 has acenter of mass that is axially aligned with a central longitudinal axisof the drive shaft 136, while the one or more abrasive elements 138(collectively and/or individually) have a center of mass that is axiallyoffset from central longitudinal axis of the drive shaft 136.Accordingly, as the drive shaft 136 is rotated about its longitudinalaxis, the principle of centrifugal force will cause the one or moreabrasive elements 138 (and the portion of the drive shaft 136 to whichthe one or more abrasive elements 138 are affixed) to follow atransverse generally circular orbit (e.g., somewhat similar to a “jumprope” orbital movement) relative to the central axis of the drive shaft136 (as described below, for example, in connection with FIGS. 4-6). Ingeneral, faster speeds (rpm) of rotation of the drive shaft 136 willresult in larger diameters of the orbit (within the limits of the vesseldiameter). The orbiting one or more abrasive elements 138 will contactthe stenotic lesion to ablate or abrade the lesion to a reduced size(i.e., small particles of the lesion will be abraded from the lesion).

The rotating distal stability element 140 will remain generally at thelongitudinal axis of the drive shaft 136 as the drive shaft 136 isrotated (as described below, for example, in connection with FIGS. 4-6).In some optional embodiments, two or more distal stability elements 140are included. As described further below, contemporaneous with therotation of the drive shaft 136, the drive shaft 136 can be translatedback and forth along the longitudinal axis of the drive shaft 136.Hence, lesions can be abraded radially and longitudinally by virtue ofthe orbital rotation and translation of the one or more abrasiveelements 138, respectively.

The flexible drive shaft 136 of rotational atherectomy system 100 islaterally flexible so that the drive shaft 136 can readily conform tothe non-linear vasculature of the patient, and so that a portion of thedrive shaft 136 at and adjacent to the one or more abrasive elements 138will laterally deflect when acted on by the centrifugal forces resultingfrom the rotation of the one or more eccentric abrasive elements 138. Inthis embodiment, the drive shaft 136 comprises one or more helicallywound wires (or filars) that provide one or more torque-transmittingcoils of the drive shaft 136 (as described below, for example, inconnection with FIGS. 7-8). In some embodiments, the one or morehelically wound wires are made of a metallic material such as, but notlimited to, stainless steel (e.g., 316, 316L, or 316LVM), nitinol,titanium, titanium alloys (e.g., titanium beta 3), carbon steel, oranother suitable metal or metal alloy. In some alternative embodiments,the filars are or include graphite, Kevlar, or a polymeric material. Insome embodiments, the filars can be woven, rather than wound. In someembodiments, individual filars can comprise multiple strands of materialthat are twisted, woven, or otherwise coupled together to form a filar.In some embodiments, the filars have different cross-sectionalgeometries (size or shape) at different portions along the axial lengthof the drive shaft 136. In some embodiments, the filars have across-sectional geometry other than a circle, e.g., an ovular, square,triangular, or another suitable shape.

In this embodiment, the drive shaft 136 has a hollow core. That is, thedrive shaft 136 defines a central longitudinal lumen runningtherethrough. The lumen can be used to slidably receive the guidewire134 therein, as will be described further below. In some embodiments,the lumen can be used to aspirate particulate or to convey fluids thatare beneficial for the atherectomy procedure.

In some embodiments, the drive shaft 136 includes an optional coating onone or more portions of the outer diameter of the drive shaft 136. Thecoating may also be described as a jacket, a sleeve, a covering, acasing, and the like. In some embodiments, the coating adds columnstrength to the drive shaft 136 to facilitate a greater ability to pushthe drive shaft 136 through stenotic lesions. In addition, the coatingcan enhance the rotational stability of the drive shaft 136 during use.In some embodiments, the coating is a flexible polymer coating thatsurrounds an outer diameter of the coil (but not the abrasive elements138 or the distal stability element 140) along at least a portion ofdrive shaft 136 (e.g., the distal portion of the drive shaft 136 exposedoutwardly from the sheath 132). In some embodiments, a portion of thedrive shaft 136 or all of the drive shaft 136 is uncoated. In particularembodiments, the coating is a fluid impermeable material such that thelumen of the drive shaft 136 provides a fluid impermeable flow pathalong at least the coated portions of the drive shaft 136.

The coating may be made of materials including, but not limited to,PEBEX, PICOFLEX, PTFE, ePTFE, FEP, PEEK, silicone, PVC, urethane,polyethylene, polypropylene, and the like, and combinations thereof. Insome embodiments, the coating covers the distal stability element 140and the distal extension portion 142, thereby leaving only the one ormore abrasive elements 138 exposed (non-coated) along the distal portionof the drive shaft 136. In alternative embodiments, the distal stabilityelement 140 is not covered with the coating, and thus would be exposedlike the abrasive element 140. In some embodiments, two or more layersof the coating can be included on portions of the drive shaft 136.Further, in some embodiments different coating materials (e.g., withdifferent durometers and/or stiffnesses) can be used at differentlocations on the drive shaft 136.

In the depicted embodiment, the distal stability element 140 is ametallic cylindrical member having an inner diameter that surrounds aportion of the outer diameter of the drive shaft 136. In someembodiments, the distal stability element 140 has a longitudinal lengththat is greater than a maximum exterior diameter of the distal stabilityelement 140. In the depicted embodiment, the distal stability element140 is coaxial with the longitudinal axis of the drive shaft 136.Therefore, the center of mass of the distal stability element 140 isaxially aligned (non-eccentric) with the longitudinal axis of the driveshaft 136. In alternative rotational atherectomy device embodiments,stability element(s) that have centers of mass that are eccentric inrelation to the longitudinal axis may be included in addition to, or asan alternative to, the coaxial stability elements 140. For example, insome alternative embodiments, the stability element(s) can have centersof mass that are eccentric in relation to the longitudinal axis and thatare offset 180 degrees (or otherwise oriented) in relation to the centerof mass of the one or more abrasive elements 138.

The distal stability element 140 may be made of a suitable biocompatiblematerial, such as a higher-density biocompatible material. For example,in some embodiments the distal stability element 140 may be made ofmetallic materials such as stainless steel, tungsten, molybdenum,iridium, cobalt, cadmium, and the like, and alloys thereof. The distalstability element 140 has a fixed outer diameter. That is, the distalstability element 140 is not an expandable member in the depictedembodiment. The distal stability element 140 may be mounted to thefilars of the drive shaft 136 using a biocompatible adhesive, bywelding, by press fitting, and the like, and by combinations thereof.The coating may also be used in some embodiments to attach or tosupplement the attachment of the distal stability element 140 to thefilars of the drive shaft 136. Alternatively, the distal stabilityelement 140 can be integrally formed as a unitary structure with thefilars of the drive shaft 136 (e.g., using filars of a different size ordensity, using filars that are double-wound to provide multiple filarlayers, or the like). The maximum outer diameter of the distal stabilityelement 140 may be smaller than the maximum outer diameters of the oneor more abrasive elements 138.

In some embodiments, the distal stability element 140 has an abrasivecoating on its exterior surface. For example, in some embodiments adiamond coating (or other suitable type of abrasive coating) is disposedon the outer surface of the distal stability element 140. In some cases,such an abrasive surface on the distal stability element 140 can helpfacilitate the passage of the distal stability element 140 throughvessel restrictions (such as calcified areas of a blood vessel).

In some embodiments, the distal stability element 140 has an exteriorcylindrical surface that is smoother and different from an abrasiveexterior surface of the one or more abrasive elements 138. That may bethe case whether or not the distal stability element 140 have anabrasive coating on its exterior surface. In some embodiments, theabrasive coating on the exterior surface of the distal stability element140 is rougher than the abrasive surfaces on the one or more abrasiveelements 138.

Still referring to FIG. 1, the one or more abrasive elements 138 (whichmay also be referred to as a burr, multiple burrs, or (optionally) ahelical array of burrs) can comprise a biocompatible material that iscoated with an abrasive media such as diamond grit, diamond particles,silicon carbide, and the like. In the depicted embodiment, the abrasiveelements 138 includes a total of five discrete abrasive elements thatare spaced apart from each other. In some embodiments, one, two, three,four, five, six, seven, eight, nine, ten, eleven, twelve, thirteen,fourteen, fifteen, or more than fifteen discrete abrasive elements areincluded as the one or more abrasive elements 138. Each of the fivediscrete abrasive elements can include the abrasive media coating, suchas a diamond grit coating.

In the depicted embodiment, the two outermost abrasive elements aresmaller in maximum diameter than the three inner abrasive elements. Insome embodiments, all of the abrasive elements are the same size. Inparticular embodiments, three or more different sizes of abrasiveelements are included. Any and all such possible arrangements of sizesof abrasive elements are envisioned and within the scope of thisdisclosure.

Also, in the depicted embodiment, the center of mass of each abrasiveelement 138 is offset from the longitudinal axis of the drive shaft 136.Therefore, as the eccentric one or more abrasive elements 138 arerotated (along an orbital path), at least a portion of the abrasivesurface of the one or more abrasive elements 138 can make contact withsurrounding stenotic lesion material. As with the distal stabilityelement 140, the eccentric one or more abrasive elements 138 may bemounted to the filars of the torque-transmitting coil of the drive shaft136 using a biocompatible adhesive, high temperature solder, welding,press fitting, and the like. In some embodiments, a hypotube is crimpedonto the driveshaft and an abrasive element is laser welded to thehypotube. Alternatively, the one or more abrasive elements 138 can beintegrally formed as a unitary structure with the filars of the driveshaft 136 (e.g., using filars that are wound in a different pattern tocreate an axially offset structure, or the like).

In some embodiments, the spacing of the distal stability element 140relative to the one or more abrasive elements 138 and the length of thedistal extension portion 142 can be selected to advantageously provide astable and predictable rotary motion profile during high-speed rotationof the drive shaft 136. For example, in embodiments that include thedistal driveshaft extension portion 142, the ratio of the length of thedistal driveshaft extension 142 to the distance between the centers ofthe one or more abrasive elements 138 and the distal stability element140 is about 1:0.5, about 1:0.8, about 1:1, about 1.1:1, about 1.2:1,about 1.5:1, about 2:1, about 2.5:1, about 3:1, or higher than 3:1.

Still referring to FIG. 1, the rotational atherectomy system 100 alsoincludes the actuator handle assembly 110. The actuator handle assembly110 includes a housing 112 and a carriage assembly 114. The carriageassembly 114 is slidably translatable along the longitudinal axis of thehandle assembly 110 as indicated by the arrow 115. For example, in someembodiments the carriage assembly 114 can be translated, withoutlimitation, about 8 cm to about 12 cm, or about 6 cm to about 10 cm, orabout 4 cm to about 8 cm, or about 6 cm to about 14 cm. As the carriageassembly 114 is translated in relation to the housing 112, the driveshaft 136 translates in relation to the sheath 132 in a correspondingmanner.

In the depicted embodiment, the carriage assembly 114 includes a valveactuator 116. In some embodiments, an electric motor for drivingrotations of the drive shaft 136 is coupled to the carriage assembly 114such that the valve actuator 116 is an electrical switch instead. In thedepicted embodiment, the valve actuator 116 is a button that can bedepressed to actuate a compressed gas control valve (on/off; defaultingto off) mounted to the carriage assembly 114. While the valve actuator116 is depressed, a compressed gas (e.g., air, nitrogen, etc.) issupplied through the valve to a turbine member that is rotatably coupledto the carriage assembly 114 and fixedly coupled to the drive shaft 136.Hence, an activation of the valve actuator 116 will result in a rotationof the turbine member and, in turn, the drive shaft 136 (as depicted byarrow 137). It should be understood that the rotational atherectomysystem 100 is configured to rotate the drive shaft 136 at a high speedof rotation (e.g., 20,000-160,000 rpm) such that the eccentric one ormore abrasive elements 138 revolve in an orbital path to thereby contactand remove portions of a target lesion (even those portions of thelesion that are spaced farther from the axis of the drive shaft 136 thanthe maximum radius of the one or more abrasive elements 138).

To operate the handle assembly 110 during a rotational atherectomyprocedure, a clinician can grasp the carriage assembly 114 and depressthe valve actuator 116 with the same hand. The clinician can move(translate) the carriage assembly 114 distally and proximally by hand(e.g., back and forth in relation to the housing 112), while maintainingthe valve actuator 116 in the depressed state. In that manner, a targetlesion(s) can be ablated radially and longitudinally by virtue of theresulting orbital rotation and translation of the one or more abrasiveelements 138, respectively.

During an atherectomy treatment, in some cases the guidewire 134 is leftin position in relation to the drive shaft 136 generally as shown. Forexample, in some cases the portion of the guidewire 134 that isextending beyond the distal end of the drive shaft 136 (or extensionportion 142) is about 10 inches to about 12 inches (about 25 cm to about30 cm), about 6 inches to about 16 inches (about 15 cm to about 40 cm),or about 2 inches to about 20 inches (about 5 cm to about 50 cm). Insome cases, the guidewire 134 is pulled back to be within (while notextending distally from) the drive shaft 136 during an atherectomytreatment. The distal end of the guidewire 134 may be positionedanywhere within the drive shaft 136 during an atherectomy treatment. Insome cases, the guidewire 134 may be completely removed from within thedrive shaft during an atherectomy treatment. The extent to which theguidewire 134 is engaged with the drive shaft 136 during an atherectomytreatment may affect the size of the orbital path of the one or moreabrasive elements 138. Accordingly, the extent to which the guidewire134 is engaged with the drive shaft 136 may be situationally selected tobe well-suited for a particular patient anatomy, physician's preference,type of treatment being delivered, and other such factors.

In the depicted embodiment, the handle assembly 110 also includes aguidewire detention mechanism 118. The guidewire detention mechanism 118can be selectively actuated (e.g., rotated) to releasably clamp andmaintain the guidewire 134 in a stationary position relative to thehandle assembly 110 (and, in turn, stationary in relation to rotationsof the drive shaft 136 during an atherectomy treatment). While the driveshaft 136 and handle assembly 110 are being advanced over the guidewire134 to put the one or more abrasive elements 138 into a targetedposition within a patient's vessel, the guidewire detention mechanism118 will be unactuated so that the handle assembly 110 is free to slidein relation to the guidewire 134. Then, when the clinician is ready tobegin the atherectomy treatment, the guidewire detention mechanism 118can be actuated to releasably detain/lock the guidewire 134 in relationto the handle assembly 110. That way the guidewire 134 will not rotatewhile the drive shaft 136 is rotating, and the guidewire 134 will nottranslate while the carriage assembly 114 is being manually translated.

Still referring to FIG. 1, the rotational atherectomy system 100 alsoincludes the controller 150. In the depicted embodiment, the controller150 includes a user interface 152 that includes a plurality ofselectable inputs 154 that correspond to a plurality of vessel sizes(diameters). To operate the rotational atherectomy system 100, the usercan select a particular one of the selectable inputs 154 thatcorresponds to the diameter of the vessel being treated. In response,the controller 150 will determine the appropriate gas pressure forrotating the drive shaft 136 in a vessel of the selected diameter(faster rpm for larger vessels and slower rpm for smaller vessel), andsupply the gas at the appropriate pressure to the handle assembly 110.

In some embodiments, the controller 150 is pole-mounted. The controller150 can be used to control particular operations of the handle assembly110 and the drive shaft assembly 130. For example, the controller 150can be used to compute, display, and adjust the rotational speed of thedrive shaft 136.

In some embodiments, the controller 150 can include electronic controlsthat are in electrical communication with a turbine RPM sensor locatedon the carriage assembly 114. The controller 150 can convert thesignal(s) from the sensor into a corresponding RPM quantity and displaythe RPM on the user interface 152. If a speed adjustment is desired, theclinician can increase or decrease the rotational speed of the driveshaft 136. In result, a flow or pressure of compressed gas supplied fromthe controller 150 to the handle assembly 110 (via the cable assembly160) will be modulated. The modulation of the flow or pressure of thecompressed gas will result in a corresponding modulation of the RPM ofthe turbine member and of the drive shaft 136.

In some embodiments, the controller 150 includes one or more interlockfeatures that can enhance the functionality of the rotationalatherectomy system 100. In one such example, if the controller 150 doesnot detect any electrical signal (or a proper signal) from the turbineRPM sensor, the controller 150 can discontinue the supply of compressedgas. In another example, if a pressure of a flush liquid supplied to thesheath 132 is below a threshold pressure value, the controller 150 candiscontinue the supply of compressed gas.

Referring also to FIGS. 2-6, the rotational atherectomy system 100 canbe used to treat a vessel 10 having a stenotic lesion 14 along an innerwall 12 of the vessel 10. The rotational atherectomy system 100 is usedto fully or partially remove the stenotic lesion 14, thereby removing orreducing the blockage within the vessel 10 caused by the stenotic lesion14. By performing such a treatment, the blood flow through the vessel 10may be thereafter increased or otherwise improved. The vessel 10 andlesion 14 are shown in longitudinal cross-sectional views to enablevisualization of the rotational atherectomy system 100.

Briefly, in some implementations the following activities may occur toachieve the deployed arrangement shown in FIGS. 2-6. In someembodiments, an introducer sheath (not shown) can be percutaneouslyadvanced into the vasculature of the patient. The guidewire 134 can thenbe inserted through a lumen of the introducer sheath and navigatedwithin the patient's vasculature to a target location (e.g., thelocation of the lesion 14). Techniques such as x-ray fluoroscopy orultrasonic imaging may be used to provide visualization of the guidewire134 and other atherectomy system components during placement. In someembodiments, no introducer sheath is used and the guidewire 134 isinserted without assistance from a sheath. The resulting arrangement isdepicted in FIG. 2.

Next, as depicted in FIG. 3, portions of the rotational atherectomysystem 100 can be inserted over the guidewire 134. For example, anopening to the lumen of the drive shaft 136 at the distal free end ofthe drive shaft 136 (e.g., at the distal end of the optional distaldrive shaft extension portion 142) can be placed onto the guidewire 134,and then the drive shaft assembly 130 and handle assembly 110 can begradually advanced over the guidewire 134 to the position in relation tothe lesion 14 as shown. In some cases, the drive shaft 136 is disposedfully within the lumen of the sheath 132 during the advancing. In somecases, a distal end portion of the drive shaft 136 extends from thedistal end opening 143 of the sheath 132 during the advancing.Eventually, after enough advancing, the proximal end of the guidewire134 will extend proximally from the handle assembly 110 (via the accessport 120 defined by the handle housing 112).

In some cases (such as in the depicted example), the lesion 14 may be solarge (i.e., so extensively occluding the vessel 10) that it isdifficult or impossible to push the distal stability element 140 throughthe lesion 14. In some such cases, an abrasive outer surface on thedistal stability element 140 can be used to help facilitate passage ofthe distal stability element 140 into or through the lesion 14. In somesuch cases, the drive shaft 136 can be rotated to further helpfacilitate the distal stability element 140 to bore into/through thelesion 14.

Next, as depicted by FIGS. 4-6, the rotation and translational motionsof the drive shaft 136 (and the one or more abrasive elements 138) canbe commenced to perform ablation of the lesion 14.

In some implementations, prior to the ablation of the lesion 14 by theone or more abrasive elements 138, an inflatable member can be used asan angioplasty balloon to treat the lesion 14. That is, an inflatablemember (on the sheath 132, for example) can be positioned within thelesion 14 and then inflated to compress the lesion 14 against the innerwall 12 of the vessel 10. Thereafter, the rotational atherectomyprocedure can be performed. In some implementations, such an inflatablemember can be used as an angioplasty balloon after the rotationalatherectomy procedure is performed. In some implementations,additionally or alternatively, a stent can be placed at lesion 14 usingan inflatable member on the sheath 132 (or another balloon memberassociated with the drive shaft assembly 130) after the rotationalatherectomy procedure is performed.

The guidewire 134 may remain extending from the distal end of the driveshaft 136 during the atherectomy procedure as shown. For example, asdepicted by FIGS. 4-6, the guidewire 134 extends through the lumen ofthe drive shaft 136 and further extends distally of the distal end ofthe distal extension portion 142 during the rotation and translationalmotions of the drive shaft 136 (refer, for example, to FIGS. 4-6). Insome alternative implementations, the guidewire 134 is withdrawncompletely out of the lumen of the drive shaft 136 prior to during therotation and translational motions of the drive shaft 136 for abradingthe lesion 14. In other implementations, the guidewire is withdrawn onlypartially. That is, in some implementations a portion of the guidewireremains within the lumen of the drive shaft 136 during rotation of thedrive shaft 136, but remains only in a proximal portion that is notsubject to the significant orbital path in the area of the one or moreabrasive elements 138 (e.g., remains within the portion of the driveshaft 136 that remains in the sheath 132).

To perform the atherectomy procedure, the drive shaft 136 is rotated ata high rate of rotation (e.g., 20,000-160,000 rpm) such that theeccentric one or more abrasive elements 138 revolve in an orbital pathabout an axis of rotation and thereby contacts and removes portions ofthe lesion 14.

Still referring to FIGS. 4-6, the rotational atherectomy system 100 isdepicted during the high-speed rotation of the drive shaft 136. Thecentrifugal force acting on the eccentrically weighted one or moreabrasive elements 138 causes the one or more abrasive elements 138 toorbit in an orbital path around the axis of rotation 139. In someimplementations, the orbital path can be somewhat similar to the orbitalmotion of a “jump rope.” As shown, some portions of the drive shaft 136(e.g., a portion that is just distal of the sheath 132 and anotherportion that is distal of the distal stability element 140) can remainin general alignment with the axis of rotation 139, but the particularportion of the drive shaft 136 adjacent to the one or more abrasiveelements 138 is not aligned with the axis of rotation 139 (and insteadorbits around the axis 139). As such, in some implementations, the axisof rotation 139 may be aligned with the longitudinal axis of a proximalpart of the drive shaft 136 (e.g., a part within the distal end of thesheath 132) and with the longitudinal axis of the distal extensionportion 142 of the drive shaft 136.

In some implementations, as the one or more abrasive elements 138rotates, the clinician operator slowly advances the carriage assembly114 distally (and, optionally, reciprocates both distally andproximally) in a longitudinal translation direction so that the abrasivesurface of the one or more abrasive elements 138 scrapes againstadditional portions of the occluding lesion 14 to reduce the size of theocclusion, and to thereby improve the blood flow through the vessel 10.This combination of rotational and translational motion of the one ormore abrasive elements 138 is depicted by the sequence of FIGS. 4-6.

In some embodiments, the sheath 132 may define one or more lumens (e.g.,the same lumen as, or another lumen than, the lumen in which the driveshaft 136 is located) that can be used for aspiration (e.g., of abradedparticles of the lesion 14). In some cases, such lumens can beadditionally or alternatively used to deliver perfusion and/ortherapeutic substances to the location of the lesion 14, or to preventbackflow of blood from vessel 10 into sheath 132.

Referring to FIG. 7, a distal end portion of the drive shaft 136 isshown in a longitudinal cross-sectional view. The distal end portion ofthe drive shaft 136 includes the one or more abrasive elements 138 thatare eccentrically-fixed to the driveshaft 136, the distal stabilityelement 140 with an abrasive outer surface, and the distal drive shaftextension portion 142.

In the depicted embodiment, the one or more abrasive elements 138includes a total of five discrete abrasive elements that are spacedapart from each other. In some embodiments, one, two, three, four, five,six, seven, eight, nine, ten, eleven, twelve, thirteen, fourteen,fifteen, or more than fifteen discrete abrasive elements are included asthe one or more abrasive elements 138. Each of the five discreteabrasive elements can include the abrasive media coating.

In the depicted embodiment, the two outermost abrasive elements of theabrasive elements 138 are smaller in maximum diameter than the threeinner abrasive elements of the abrasive elements 138. In someembodiments, all of the abrasive elements are the same size. Inparticular embodiments, three or more different sizes of abrasiveelements are included. Any and all such possible arrangements of sizesof abrasive elements are envisioned and within the scope of thisdisclosure.

The one or more abrasive elements 138 can be made to any suitable size.For clarity, the size of the one or more abrasive elements 138 willrefer herein to the maximum outer diameter of individual abrasiveelements of the one or more abrasive elements 138. In some embodiments,the one or more abrasive elements 138 are about 2 mm in size (maximumouter diameter). In some embodiments, the size of the one or moreabrasive elements 138 is in a range of about 1.5 mm to about 2.5 mm, orabout 1.0 mm to about 3.0 mm, or about 0.5 mm to about 4.0 mm, withoutlimitation. Again, in a single embodiment, one or more of the abrasiveelements 138 can have a different size in comparison to the otherabrasive elements 138. In some embodiments, the two outermost abrasiveelements are about 1.5 mm in diameter and the inner abrasive elementsare about 2.0 mm in diameter.

In the depicted embodiment, the one or more abrasive elements 138,individually, are oblong in shape. A variety of different shapes can beused for the one or more abrasive elements 138. For example, in someembodiments the one or more abrasive elements 138 are individuallyshaped as spheres, discs, rods, cylinders, polyhedrons, cubes, prisms,and the like. In some embodiments, such as the depicted embodiment, allof the one or more abrasive elements 138 are the same shape. Inparticular embodiments, one or more of the abrasive elements 138 has adifferent shape than one or more of the other abrasive elements 138.That is, two, three, or more differing shapes of individual abrasiveelements 138 can be combined on the same drive shaft 136.

In the depicted embodiment, adjacent abrasive elements of the one ormore abrasive elements 138 are spaced apart from each other. Forexample, in the depicted embodiment the two distal-most individualabrasive elements are spaced apart from each other by a distance ‘X’. Insome embodiments, the spacing between adjacent abrasive elements isconsistent between all of the one or more abrasive elements 138.Alternatively, in some embodiments the spacing between some adjacentpairs of abrasive elements differs from the spacing between otheradjacent pairs of abrasive elements.

In some embodiments, the spacing distance X in ratio to the maximumdiameter of the abrasive elements 138 is about 1:1. That is, the spacingdistance X is about equal to the maximum diameter. The spacing distanceX can be selected to provide a desired degree of flexibility of theportion of the drive shaft 136 to which the one or more abrasiveelements 138 are attached. In some embodiments, the ratio is about 1.5:1(i.e., X is about 1.5 times longer than the maximum diameter). In someembodiments, the ratio is in a range of about 0.2:1 to about 0.4:1, orabout 0.4:1 to about 0.6:1, or about 0.6:1 to about 0.8:1, or about0.8:1 to about 1:1, or about 1:1 to about 1.2:1, or about 1.2:1 to about1.4:1, or about 1.4:1 to about 1.6:1, or about 1.6:1 to about 1.8:1, orabout 1.8:1 to about 2.0:1, or about 2.0:1 to about 2.2:1, or about2.2:1 to about 2.4:1, or about 2.4:1 to about 3.0:1, or about 3.0:1 toabout 4.0:1, and anywhere between or beyond those ranges.

In the depicted embodiment, the center of mass of each one of the one ormore abrasive elements 138 is offset from the longitudinal axis of thedrive shaft 136 along a same radial angle. Said another way, the centersof mass of all of the one or more abrasive elements 138 are coplanarwith the longitudinal axis of the drive shaft 136. If the size of eachof the one or more abrasive elements 138 is equal, the centers of massof the one or more abrasive elements 138 would be collinear on a linethat is parallel to the longitudinal axis of the drive shaft 136.

Referring to FIG. 8, according to some embodiments of the rotationalatherectomy devices provided herein, one or more abrasive elements 144are arranged at differing radial angles in relation to the drive shaft136. In such a case, a path defined by the centers of mass of the one ormore abrasive elements 144 spirals along the drive shaft 136. In somecases (e.g., when the diameters of the one or more abrasive elements 144are equal and the adjacent abrasive elements are all equally spaced),the centers of mass of the one or more abrasive elements 144 define ahelical path along/around the drive shaft 136. It has been found thatsuch arrangements can provide a desirably-shaped orbital rotation of theone or more abrasive elements 144.

It should be understood that any of the structural features described inthe context of one embodiment of the rotational atherectomy devicesprovided herein can be combined with any of the structural featuresdescribed in the context of one or more other embodiments of therotational atherectomy devices provided herein. For example, the sizeand/or shape features of the one or more abrasive elements 138 can beincorporated in any desired combination with the spiral arrangement ofthe one or more abrasive elements 144.

Referring also to FIGS. 9-13, the differing radial angles of theindividual abrasive elements 144 a, 144 b, 144 c, 144 d, and 144 e canbe further visualized. To avoid confusion, each figure of FIGS. 9-13illustrates only the closest one of the individual abrasive elements 144a, 144 b, 144 c, 144 d, and 144 e (i.e., closest in terms of thecorresponding cutting-plane as shown in FIG. 8). For example, in FIG.10, abrasive element 144 b is shown, but abrasive element 144 a is notshown (so that the radial orientation of the abrasive element 144 b isclearly depicted).

It can be seen in FIGS. 9-13 that the centers of mass of abrasiveelements 144 a, 144 b, 144 c, 144 d, and 144 e are at differing radialangles in relation to the drive shaft 136. Hence, it can be said thatthe abrasive elements 144 a, 144 b, 144 c, 144 d, and 144 e are disposedat differing radial angles in relation to the drive shaft 136.

In the depicted embodiment, the radial angles of the abrasive elements144 a, 144 b, 144 c, 144 d, and 144 e differ from each other by aconsistent 37.5 degrees (approximately) in comparison to the adjacentabrasive element(s). For example, the center of mass of abrasive element144 b is disposed at a radial angle B that is about 37.5 degreesdifferent than the angle at which the center of mass of abrasive element144 a is disposed, and about 37.5 degrees different than the angle C atwhich the center of mass of abrasive element 144 c is disposed.Similarly, the center of mass of abrasive element 144 c is disposed at aradial angle C that is about 37.5 degrees different than the angle B atwhich the center of mass of abrasive element 144 b is disposed, andabout 37.5 degrees different than the angle D at which the center ofmass of abrasive element 144 d is disposed. The same type of relativerelationships can be said about abrasive element 144 d.

While the depicted embodiment has a relative radial offset of 37.5degrees (approximately) in comparison to the adjacent abrasiveelement(s), a variety of other relative radial offsets are envisioned.For example, in some embodiments the relative radial offsets of theadjacent abrasive elements is in a range of about 0 degrees to about 5degrees, or about 5 degrees to about 10 degrees, or about 10 degrees toabout 15 degrees, or about 15 degrees to about 20 degrees, or about 20degrees to about 25 degrees, or about 25 degrees to about 30 degrees, orabout 30 degrees to about 35 degrees, or about 10 degrees to about 30degrees, or about 20 degrees to about 40 degrees, or about 20 degrees toabout 50 degrees.

While in the depicted embodiment, the relative radial offsets of theabrasive elements 144 a, 144 b, 144 c, 144 d, and 144 e in comparison tothe adjacent abrasive element(s) are consistent, in some embodimentssome abrasive elements are radially offset to a greater or lesser extentthan others. For example, while angles B, C, D, and E are all multiplesof 37.5 degrees, in some embodiments one or more of the angles B, C, D,and/or E is not a multiple of the same angle as the others.

The direction of the spiral defined by the centers of mass of theabrasive elements 144 a, 144 b, 144 c, 144 d, and 144 e can be in eitherdirection around the drive shaft 136, and in either the same directionas the wind of the filars or in the opposing direction as the wind ofthe filars.

Referring to FIG. 14, the rotational atherectomy system 100 alsoincludes the controller 150. In the depicted embodiment, the controller150 includes a user interface 152 that includes a plurality ofselectable inputs 154 that correspond to a plurality of vessel sizes(diameters). Other types of user interfaces are also envisioned (e.g.,refer to FIG. 16). To operate the rotational atherectomy system 100, theuser can select a particular one of the selectable inputs 154 thatcorresponds to the diameter of the vessel being treated. In response,the controller 150 will determine the appropriate gas pressure forrotating the one or more abrasive elements 138 in a vessel of theselected diameter (faster rpm for larger vessels and slower rpm forsmaller vessel), and supply the gas at the appropriate pressure to thehandle assembly 110. In some embodiments, the driver for rotation of theone or more abrasive elements 138 is an electrical motor rather than thepneumatic motor included in the depicted example.

In the depicted example, the vessel to be treated is in a leg 10 of apatient. In particular, the vessel is below a knee 12 (e.g., an tibialartery, without limitation). Such a vessel can tend to be relativelysmall in diameter. Therefore, in this illustrative example, theclinician user is inputting a vessel size of 4.0 mm. In response, thecontroller 150 will determine the appropriate gas pressure for rotatingthe one or more abrasive elements 138 in a 4.0 mm vessel. For example,that speed may be about 40,000 rpm. The corresponding gas pressure willbe supplied to the handle assembly 110 via cable assembly 160 (FIG. 1).

Referring to FIG. 15, in another example, the vessel to be treated isabove the knee 12. For example, without limitation, the vessel may be aniliac or femoral artery. Such a vessel will tend to be relatively largein diameter. Therefore, in this illustrative example, the clinician useris inputting a vessel size of 8.0 mm. In response, the controller 150will determine the appropriate gas pressure for rotating the one or moreabrasive elements 138 in an 8.0 mm vessel. For example, that speed maybe about 80,000 rpm. The corresponding gas pressure will be supplied tothe handle assembly 110 via cable assembly 160 (FIG. 1).

Referring to FIG. 16, in some embodiments the rotational atherectomysystems described herein can include a controller 250 that has isconfigured with an example user interface 252. The user interface 252includes readily understandable and convenient-to-use selectable inputs254 that correspond to the rotational speed at which the drive shaftwill be driven by the controller 250.

In this example, the user interface 252 is configured such that the usercan simply select either “LOW,” “MED,” or “HIGH” speed via theselectable inputs 254. Based on the user's selection of either “LOW,”“MED,” or “HIGH,” the controller 250 will provide a corresponding outputfor rotating the drive shaft at a corresponding rotational speed. Itshould be understood that the user interfaces 152 (e.g., FIGS. 14 and15) and 252 are merely exemplary and non-limiting. That is, other typesof user interface controls can also be suitably used, and are envisionedwithin the scope of this disclosure.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, design features of the embodiments described herein can becombined with other design features of other embodiments describedherein. Accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A rotational atherectomy device for removing stenotic lesion material from a blood vessel of a patient, the device comprising: an elongate flexible drive shaft comprising a torque-transmitting coil and defining a longitudinal axis, the drive shaft being configured to rotate about the longitudinal axis; first and second abrasive elements attached to a distal end portion of the drive shaft and each having a center of mass offset from the longitudinal axis, the center of mass of the first abrasive element being offset from the longitudinal axis at a first radial angle, the center of mass of the second abrasive element being offset from the longitudinal axis at a second radial angle that differs from the first radial angle; and a distal stability element fixedly mounted to the drive shaft and having a center of mass aligned with the longitudinal axis, the distal stability element being distally spaced apart from the first and second abrasive elements.
 2. The device of claim 1, further comprising a third abrasive element attached to the distal end portion of the drive shaft, wherein the center of mass of the third abrasive element is offset from the longitudinal axis along a third radial angle that differs from the first radial angle and the second radial angle.
 3. The device of claim 2, wherein the second radial angle differs from the first radial angle by at least 15 degrees, and wherein the third radial angle differs from the first radial angle and the second radial angle by at least 15 degrees.
 4. The device of claim 1, wherein the distal stability element comprises a metal cylinder surrounding the torque-transmitting coil of the drive shaft and having a maximum diameter smaller than the first and second abrasive elements, and wherein the distal stability element has an abrasive outer surface.
 5. The device of claim 1, further comprising an array of abrasive elements including the first and second abrasive elements and additional abrasive elements attached to the distal end portion of the drive shaft, wherein a proximal-most one of the array of abrasive elements and a distal-most one of the array of abrasives element are each smaller than intermediate ones of the array of abrasive elements.
 6. The device of claim 5, wherein a path defined by the centers of mass of the array of abrasive elements define at least a portion of a helical path around the longitudinal axis.
 7. The device of claim 1, further comprising a flexible polymer coating along the drive shaft such that the coating surrounds an outer diameter of at least a portion of drive shaft.
 8. A rotational atherectomy device for removing stenotic lesion material from a blood vessel of a patient, the device comprising: an elongate flexible drive shaft comprising a torque-transmitting coil and defining a longitudinal axis, the drive shaft being configured to rotate about the longitudinal axis; a helical array of abrasive elements attached to a distal end portion of the drive shaft, each of the abrasive elements having a center of mass that is offset from the longitudinal axis, the centers of mass of the abrasive elements being noncollinear; and a distal stability element affixed to the drive shaft and having a center of mass aligned with the longitudinal axis, the distal stability element distally spaced apart from the plurality of abrasive elements.
 9. The device of claim 8, further comprising a flexible polymer coating along the drive shaft such that the coating surrounds an outer diameter of at least a portion of drive shaft.
 10. The device of claim 8, wherein the drive shaft comprises a distal-most extension portion that extends distally of the distal stability element for a distal extension distance.
 11. The device of claim 8, wherein the drive shaft has a central lumen configured to receive a guidewire extending along the longitudinal axis.
 12. The device of claim 8, wherein the distal stability element comprises a metal cylinder surrounding the torque-transmitting coil, and wherein the metal cylinder has an abrasive outer surface.
 13. The device of claim 8, wherein the plurality of abrasive elements are spaced apart from each other by at least 50% of an outer diameter of a largest one of the abrasive elements.
 14. The device of claim 8, wherein a proximal-most one of the abrasive elements and a distal-most one of the abrasives element are each smaller than intermediate ones of the abrasive elements.
 15. The device of claim 8, wherein a path defined by the centers of mass of sequential abrasive elements of plurality the abrasive elements spirals around the longitudinal axis.
 16. The device of claim 15, wherein the plurality of abrasive elements comprises five abrasive elements.
 17. The device of claim 1, further comprising: an actuator handle assembly configured to drive rotation of the drive shaft about the longitudinal axis, the actuator handle assembly comprising a carriage assembly that is movable in relation to other portions of the actuator handle assembly to translate the drive shaft along the longitudinal axis; and a sheath extending from the actuator handle assembly, the drive shaft slidably disposed within a lumen defined by the sheath.
 18. A system for performing rotational atherectomy to remove stenotic lesion material from a blood vessel of a patient, the system comprising: an elongate flexible drive shaft comprising a torque-transmitting coil and defining a longitudinal axis, the drive shaft being configured to rotate about the longitudinal axis; one or more abrasive elements attached to a distal end portion of the drive shaft, each of the abrasive elements having a center of mass that is offset from the longitudinal axis; a distal stability element fixed to the drive shaft and having a center of mass aligned with the longitudinal axis, the distal stability element distally spaced apart from the plurality of abrasive elements; an actuator handle assembly configured to drive rotation of the drive shaft about the longitudinal axis, the actuator handle assembly comprising a carriage assembly that is movable in relation to other portions of the actuator handle assembly to translate the drive shaft along the longitudinal axis; a sheath extending from the actuator handle assembly, the drive shaft slidably disposed within a lumen defined by the sheath; and a controller operably coupleable to the actuator handle assembly, the controller configured to provide output to the actuator handle assembly that causes the actuator handle assembly to drive the rotation of the drive shaft about the longitudinal axis, the controller including a user interface with a plurality of selectable inputs corresponding to a plurality of vessel sizes, wherein controller is configured to provide a respective output to the actuator handle assembly that differs for each of the vessel sizes.
 19. The system of claim 18, wherein a center of mass of a first one of the abrasive elements is transversely offset from the longitudinal axis along a first angle, and wherein a center of mass of a second one of the abrasive elements is transversely offset from the longitudinal axis along a second angle that differs from the first angle by at least 15 degrees.
 20. The system of claim 18, further comprising a flexible polymer coating along the drive shaft such that the coating surrounds an outer diameter of at least a portion of drive shaft, and wherein the distal stability element has an abrasive outer surface.
 21. A method for performing rotational atherectomy to remove stenotic lesion material from a blood vessel of a patient, the method comprising: delivering a rotational atherectomy device into the blood vessel, wherein the rotational atherectomy device comprises: an elongate flexible drive shaft comprising a torque-transmitting coil and defining a longitudinal axis, the drive shaft being configured to rotate about the longitudinal axis; a helical array of abrasive elements attached to a distal end portion of the drive shaft, each of the abrasive elements having a center of mass that is offset from the longitudinal axis, the centers of mass of the abrasive elements arranged along a path that spirals around the longitudinal axis; and a distal stability element affixed to the drive shaft and having a center of mass aligned with the longitudinal axis, the distal stability element distally spaced apart from the plurality of abrasive elements; and rotating the drive shaft about the longitudinal axis such that the abrasive elements orbit around the longitudinal axis. 